1. Field of the Invention
The present invention relates to an information distribution service for accepting an information distribution request from a terminal connected through a network and transmitting the requested information to the terminal and a distribution method for distributing the requested information to a terminal in the information distribution apparatus and information distribution system.
2. Description of the Related Art
Recently, a gigantic information network called the Internet has been constructed and utilized through mutual connections of computers and computer networks in the world. On this gigantic information network, various services are put into practical use and users can utilize various services distributed around the world while staying at home.
As an example, there is provided an information distribution service called the World Wide Web (WWW). In the World Wide Web, information which may be disclosed in general or only to limited persons is stored on a server computer connected to the gigantic information network. A user at a remote computer or other device capable of communicating via the Internet (hereafter referred to as a “terminal”) is capable of making access to nearly any information on any server connected to the Internet by connecting the terminal to such server via the Internet. In other words, users can access the information scattered throughout the world while staying at home or anywhere.
To make it possible for a user to transmit or receive the information available via the Internet without relation to the type of computer used, not only must a common protocol (for example, TCP/IP) be used for data transmission and reception, but also the content of information to be received and transmitted must be in a common format and language. One description language that is commonly used is Hyper Text Markup Language (HTML). A user is capable of browsing information in HTML by making use of general purpose browser software such as well known Netscape Navigator® and Microsoft® Internet Explorer.
At the beginning, HTML has developed by mainly describing the content of information. At present, a link function is fulfilled with which it is now possible to make reference to remote information from a “web page” of information written in HTML by providing an address of the remote information. Since a large amount of information is scattered on the Internet, evaluation for the worth of the information itself and the worth of the location of information is desired and a structured language fulfilling the link function such as extensible markup language (XML) is now being developed. XML improves on HTML by providing an independent link function.
Therefore, the information providing server is now capable of presenting not only its own information but also information from another server by making reference thereto. Namely, information may exist at any device which may be accessed through the network and as the method for presenting information, it is also possible to register the information and present only the location of information depending on the presentation purpose. In other words, the information presenting side (web server) and the terminal to which the information is presented are now capable of respectively presenting and browsing information easily in a wider range.
However, fulfillment of function of a structured language such as XML requires improvement in the browser software for browsing information described with the structured language. Moreover, information existing on the network is versatile not only in its amount but also in the registration modes and the related information is not always described with the structured language. As an example, link destinations may be generated with word-processor software and stored in a mode depending on the word-processor software. In this case, when such word-processor software is installed at the terminal operated by a user, such word-processor software is automatically used to display the link destination information, but if such software is not installed, a user may be unable to reference the link destination information.
Terminals which may be connected to the Internet or other network include various devices ranging from a personal computer which assures as required the full functions to a hand-held telephone set which is inevitably restricted in its functions. Hand-held telephone sets which previously have been provided only with the functions of conversation through audio communication and reception/transmission of text, such as e-mail and pages are now being given an interface, like the i-mode function, that enables Internet communication and a browser function, although this function is more limited than the function of a personal computer. In the case of a hand-held telephone set, there are such restrictions on the browser function and the display area is small, but it is possible for a hand-held telephone set to enjoy the information distribution service through connection with the WWW explained above using limited browser function.
In addition, currently available are a television receiver called a Web TV and digital televisions which include a connection to the Internet. Such television receivers assure easy reception of the information via the Internet by using a remote control unit or wireless keyboard.
As explained above, the environment for utilizing the Internet is diversified and the types of information resources available via the Internet service are also diversified. There is a great deal of variation in the type of terminals connected to the Internet and the functions they perform. As a result, the service environment varies depending on the types and functions of the terminals connected thereto. In addition, even when the type and function of terminals are identical, the software installation and version conditions may be different. Namely, there are numerously different conditions depending on users and environment patterns. On the other hand, although there is great variety in the information available via the Internet, all of the information is defined and known on the information distributing side of the Internet.
When a user tries to browse the information on the Internet, the user expects, regardless of what type of terminal is used, that the information to be displayed is always displayed correctly. However, actually, if the environment of the terminal used is deviated from the environment required to correctly display the obtained information, the information cannot be displayed adequately or may be displayed in a meaningless condition. A practical example of such display condition will be explained below. As the first example, it is assumed that information described using XML is obtained using a browser which only supports a link of one direction of HTML. If a two-way link not supported by HTML is included in the obtained information, the browser cannot recognize such link and does not display that the link is extended or description of the structured language indicating the link is displayed as if it were a part of the content of information. In this case, even when a user has obtained the information, he cannot correctly recognize the content of information and cannot effectively use such information.
As the second example, it is assumed that the information requested by the browser is not described with a structured language such as HTML but has been generated with a word processor. In this case, it is no longer possible to make reference to the information if the word processor software used to generate the information is not installed at the user terminal from which the information is requested. In this case, it cannot be said that information is smoothly distributed to users.
To avoid these problems, it usually is assumed that the user terminal is always set in the latest condition. However, since the environment changes quickly in the field of the Internet and computers, based on quick technical innovation, and the type of terminal and applications installed also change more and more quickly in wider range, it is not easy to cope with such quick changes. Moreover, if it is impossible to process the distributed information, it is now discussed to provide the function of converting the information so that the terminal can process it. However, in this case, maintenance of the converting function is required in response to newly distributed or improved functions and it is difficult to always provide the latest function because of quick changes in the converting functions.
Moreover, even on the information distributing side of the Internet, maintenance of information already registered will require, depending on the amount of information and extent of expansion in function, much working load. Therefore, changes in information formats are usually not performed unless there is a change of information content. In addition, information is generated in a plurality of formats depending on the intrinsic format of the applications used to generate the information, while information is transmitted by selecting the transmission mode depending on the environment of the terminal. However, it is not preferable that the same information exists in a plurality of different formats because adequate maintenance is not always performed to all formats of information when maintenance of the information is required. Moreover, it is presumed that there is a difference in when the maintenance of each format occurs, even when maintenance is conducted to all formats of information. Furthermore, the memory capacity for storing the information increases as the number of information formats to be stored increases.